Linux Real-Time target Becomes Unreachable Through NI MAX After NI-IMAQdx 18.5 Software Install

Updated Nov 28, 2018

Reported In


  • NI-IMAQdx
  • NI-TimeSync

Issue Details

I have a Linux Real-Time target with a USB 3.0 Vision camera connected, and sometimes on reboot I cannot access the target through NI MAX and System Configuration calls will hang. What should I do about this?


This is a known issue with NI Network Discovery on NI Linux Real-Time Intel x64 and ARM targets. The 18.5 software stack exposes a conflict between the NI-IMAQdx driver and the NI Network Discovery expert, which is a dependency of the NI-TimeSync driver.
If you have a NI Linux Real-Time target with the NI-IMAQdx 18.5 and NI-TimeSync driver installed with a USB3 Vision camera connected, it is possible for you to see the following behaviors:
  • Target is unreachable in NI MAX and cannot be added by IP address
  • LabVIEW will hang when using the System Configuration API remotely from the host to access the target
  • LabVIEW might hang when using the System Configuration API on the target

This is not an exhaustive list but points out the main behaviors you could potentially run into.
To prevent this from happening, there are a few possible workarounds:

If you are not using NI-TimeSync:

  1. Unplug the USB3 Vision camera and reboot the controller to get it back to a good state
  2. Uninstall NI-TimeSync

Figure 1: Software Set Installation with the NI-TimeSync Driver Deselected
  1. Once the controller reboots, you can plug the USB 3.0 Vision Camera back in.

If you need to use NI-TimeSync:

  1. Unplug the USB camera and reboot the controller to get it back to a good state.
  2. Modify the nisysapi.ini file to ensure that NI Network Discovery, represented by the section [NIDISCEXP], is listed first.
    • Use FTP or WebDAV to transfer the nisysapi.ini file onto the Host computer to edit it. The file is located under: /usr/local/natinst/share/nisysapi.ini. Be sure to make a backup copy of it.
    • In the .ini file, move the [NIDISCEXP] section to the top.

Figure 2: Example of sysapi.ini File

The following image is an example of how your .ini file might look after you’ve made the changes. Depending on the software stack you have installed, your .ini file might have different sections in a different order. The only thing that matters is that the [NIDISCEXP] section must be listed at the top of the file.
  • Save the file and copy it back onto the Real-Time target to overwrite the original nisysapi.ini file.
  • Plug the USB 3.0 Vision Camera back in, and reboot the target


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